1. Field of the Invention
The present invention relates generally to a touch unit, and more particularly to a touch unit, which has a greatly reduced thickness and is manufactured at lower cost.
2. Description of the Related Art
Along with the rapid development of information techniques and communication networks, various personal electronic information products have been more and more popularly used. To go with the tide, various touch panels have bee rapidly developed and applied to the electronic products. According to the sensing principle, the current touch panels can be mainly classified into resistive touch panels, capacitive touch panels, electromagnetic touch panels and optical touch panels. The capacitive touch panel structures have the advantages of dustproof, fireproof and high-resolution performances and are thus widely used. The working principle of the capacitive touch panel is that the touch point position is identified according to the change of capacitance. When a conductive touch article (such as a finger) gets close to the touch panel, the capacitance between the electrodes changes to identify the coordinates of the touch point.
The capacitive touch panels have gradually become the mainstream of touch techniques and are widely applied to various electronic information products nowadays, such as cellular phones, tablets, walkmans, handheld electronic devices, displays and monitors. The capacitive touch panel can detect the capacitance change caused by the weak current of human body to identify the positions of the finger and touch selection conditions so as to achieve the object of touch control.
Most of the conventional capacitive multipoint touch panels are double-board touch panels. The double-board touch panel is made of transparent conductive substrates by means of several times of halftone printing processes or lithography processes. The transparent conductive substrate are generally made of glass and coated with indium tin oxide (ITO) coatings. The unit price of the transparent conductive substrate is quite high. Moreover, in manufacturing, much material is wasted. In case that a defective product is produced in the manufacturing process, it is necessary to discard the entire touch panel without possibility of recovery. This results in waste of cost. Moreover, the touch panel is made of the transparent conductive substrates by means of several times of halftone printing processes or lithography processes. The transparent conductive substrates are respectively coated with the indium tin oxide (ITO) coatings. Such processes are complicated so that the manufacturing cost is greatly increased. Moreover, the double-board touch panel will increase the total thickness of the electronic device. This fails to meet the requirement for lightweight, slim and miniaturized structure of portable electronic device.
According to the above, the conventional touch panel has the following shortcomings:
1. The conventional touch panel has a larger thickness.
2. The manufacturing processes of the conventional touch panel are complicated. The manufacturing cost of the conventional touch panel is higher.